This disclosure relates to an airfoil for a gas turbine engine. More particularly, the disclosure relates to a core and corresponding trailing edge passage for an airfoil.
Airfoils for gas turbine engines typically include rather complex internal cooling passages receiving cooling fluid from a cooling source. The passages are provided by core structures constructed from ceramic and/or refractory metal cores, which provide correspondingly shaped cooling passages within the airfoil.
One type of cooling passage includes a trailing edge cooling passage extending in a chord-wise direction from a radially extending cooling passage. The trailing edge cooling passage exits the trailing edge and can be relatively narrow. Depending upon the size of the trailing edge cooling passage, which may be as little as 0.008 inch (0.20 mm), and, as a result, the corresponding core is fragile.
As turbine inlet temperatures increase to prove engine thrust and cycle efficiency, advanced technologies are required to cool the trailing edge of turbine blades while minimizing the amount of cooling flow used. Use of refractory metal cores (RMC) to create high density patterns of cast cooling features has been shown to improve high convective heat transfer at low cooling flow requirements. However, the cores used to manufacture these features, such as a dense pattern of pedestals, are fragile and may break during assembly or casting.